Open the VPJ project file in Notepad. To see the VPJ, choose All Files at the bottom-right.
At the very top of the VPJ file, change the version # from 12 to 11 and <File |Save>.. Now it will prompt when you attempt to run the project in the above suggested 'stable' release, but it should load.
210 Gigs won't be practical; save your effort. Instead, see if you can delete all except a small segment of the project that has the issue. Then upload and share, using the back-up folder procedure suggested above. Before making changes... Save Project File AS routinely, giving it a unique # or name, so as not to overwrite prior saves. Using Save Project Files (no AS) will overwrite. From the HOME tab, that choice is available by clicking the chevron to the right of the Save Project button on the toolbar.
Other things to try...
If VP will launch, go to OPTIONS | EDITING tab and in the Advanced | Video Processor area at the bottom click on Default. Choose NONE (CPU) only. Then restart Videopad and before loading anything go to OPTIONS | DISK tab and Clear Unused Cache Files.
Restart it again with a right-click | Run As Administrator. Load the project.
If it continues to fail test the project on another PC, if possible.